The super-powered white dog from the planet Krypton
that is the pet and canine companion of Superman.
A member of the
Legion of Super-Pets, Krypto wears
a yellow dog collar and a flowing red-and-yellow cape modeled after
Superman's. The texts frequently refer to Krypto as the Dog of Steel.

As a puppy on the planet Krypton, where he had no super-powers, Krypto
was the playful pet of baby Kal-El, the infant Superman. But
as the hour of Krypton's doom drew ever closer, Superman's father,
Jor-El, nursing
the faint hope that his ongoing "experiments with small rockets" might
yet save his son, launched Krypto into outer space in a tiny rocket
as a final trial run, intending for the dog-carrying rocket to return
safely to Krypton after making one or more orbits of the planet.
"By a cosmic mischance," however, "a meteor struck the trial rocket
out of orbit" and sent it careening into space, and although Jor-El
did succeed in launching his infant son toward Earth in the final
moments of the cataclysm, Krypto appeared lost forever in the
interplanetary void. For years, the rocket bearing Krypto
drifted through space, ultimately to arrive on Earth, where, like any native
of Krypton, Krypto acquired super-powers like Superman's and
was happily reunited with his beloved master, who was at that time a
teen-ager growing up in Smallville in the home of his foster
parents, Jonathan and Martha Kent.

Superboy - the teenaged Superman - fashioned a cape for Krypto
modeled after his own, and Krypto, now grown into a fully developed
"superdog," became his frequent companion in super-heroic adventures.

Krypto's super-powers - including X-ray vision, super-strength,
invulnerability, and the power of flight - are similar, if not
identical, to Superman's own, although his strength is
undoubtedly not as great as Superman's, just as the strength of
an ordinary dog is not as great as that of an ordinary man.
On the other hand, however, Krypto's super-hearing and "super-keen
sense of smell" are probably more acute in a canine that in an ordinary
human being. Like any surviving native of Krypton, Krypto the Superdog
is vulnerable to
kryptonite.

Described as Superman's "faithful pet super-dog", Krypto is fully
aware that his master, Superman, is also Clark Kent.

Krypto loves to romp and play in outer space, visiting distant worlds;
cavorting in and about his
Doghouse of Solitude,
a large floating
doghouse which he has constructed out of meteoric fragments;
and mischievously chasing comets, "just as Earth-dogs chase cars!"

In order to summon Krypto home from his distant wanderings, Superman
either signals him by whistling at a highly pitched supersonic
frequency which only Krypto's ears can hear, or else summons him
by means of "super-ventriloquism," a ventriloquistic technique that enables
Superman to throw his voice over exceedingly long distances.
On at least one occasion, when absolute secrecy is called for,
the Man of Steel employes "supersonic ventriloquism," a form of
super-ventriloquism in which Superman's voice is pitched so high
that only Krypto can hear it.

Krypto, for his part, communicates with Superman by means of a
special "barking code" - similar to Morse code - taught to
him by Superman when the Man of Steel was a teenager.